Hook pin assemblies have been known for numerous years in robotic and manufacturing applications. A hook pin assembly may in one type of application be used with a robot end effector to hook a work piece or material to a specified work station such that an operation can be performed on the work piece. A specific prior art example hook pin assembly can be found in the automobile industry, there the hook pin assemblies are used to secure an automobile body to a frame assembly, wherein the frame assembly is connected to and moves the automobile body down a manufacturing line. The assemblies are used in conjunction with a hook mechanism which enters the hook pin assembly and clamps against a stop surface. Generally, the hook is placed with a force thereupon to ensure the hook is not disengaged from the pin during operation of the work piece in the work environment.
Prior art hook pin assemblies include a single unitary hook pin unit. These prior art hook pin units generally have a rectangular portion that includes an appendage extending from one side of the rectangular portion. The prior art hook pin units also include a channel through the appendage of the hook pin unit along an axis of the appendage. The channel extends completely through both outer surfaces of the appendage and creates a locking surface to which a hook will engage during work piece operations. The rectangular portions of a prior art hook pin unit includes a plurality of holes such that it can be connected to an end effector of a robot or to a work piece unit depending on the configuration of the work environment.
However, there have been problems in the prior art with hook pin units such as if a pin fails the entire line has to be stopped to replace the hook pin unit. This reduces productivity and increases the cost of manufacturing the work piece article. Furthermore, the one piece pin units are more complicated to make and often tend to be very heavy. Also the prior art hook pin units are not robust and had to be replaced frequently. Many of the prior art hook pin units are designed to hold at one holding point with one force and cannot vary their holding force unless a complete new prior art hook unit is designed. Furthermore, many of the prior art hook pin units were very susceptible to weld slag contamination thus reducing the reliability and life cycle of such hook pin units.
Therefore, there is a need in the art for an improved hook pin assembly that reduce costs, is stronger, more robust, is immune to weld slag, has a longer life cycle, is capable at operating at variable thicknesses, is capable of having a high holding force over a more varied range and is easier to maintain and repair in the work place environment.